• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.281-284
• /
• 2001

This paper presents implementation of digitally speed sensorless control system for induction motor with a direct torque control(DTC) using 32bit DSP TMS320C31. The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, MRAS with rotor flux linkages for the speed turning signal, two hysteresis controllers, optimal switching look-up table and IGBT voltage source inverter. There are suggested a control algorithm and system, and given simulation and implementation results on the 2.2Kw general purposed induction motor.

• 한국유체기계학회 논문집
• /
• 제2권1호
• /
• pp.64-72
• /
• 1999

CSCM upwind flux difference splitting compressible Navier-Stokes method has been used to predict the transonic flows in a centrifugal compressor diffuser. The modified cyclic. TDMA and the mass flux boundary conditions were used as boundary conditions of the diffuser analysis. Broad flow separation on the suction surface near the hub and shroud was observed from the results of the mass flow rates 5.8, 6.0 and 6.2kg/s at 27000 rpm. The three-dimensional flow analysis predicted successfully that the static pressure increased and the total pressure decreased through the flow passage of the channel diffuser when compared to two-dimensional analysis due to the strong effect of the three-dimensional flow. The mass averaged loss coefficients and pressure coefficients were also studied.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 A
• /
• pp.109-111
• /
• 1997

A sensorless drive of induction motor has several advantages; low cost and mechanical simplicity. This paper investigates a field-oriented control method without speed and flux sensors. The control strategy is to design an adaptive state observer for flux estimation and to estimate the rotor speed from the estimated rotor flux and stator current. The entire control algorithm including space vector PWM is implemented by software of the digital signal processor TMS320C31. The experimental results indicate good speed responses.

• 유공압시스템학회논문집
• /
• 제8권1호
• /
• pp.26-31
• /
• 2011

To drive hydraulic valve is used Linear force motor, whose force and direction are controlled by electronic signals. Linear force motor has complicated figure and its force produced by changing of flux density which is produced by permanent magnet and electrical winding. Therefore it is needed an exact calculation of the flux density. In this paper a Linear force motor is designed and analysed by 3d program Flu calculating the flux density in air gap and in yoke, Force by different current. The analysed data will be tested by prototype Linear force motor. The data and analysing method can be used for designing Linear force motor.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.660-662
• /
• 2000

It is demonstrated that the torque performance of the flux barrier type synchronous reluctance motor(SynRM) can be improved in terms of geometric parameters. Torque ana power factor are related to the difference of inductances and the saliency ratio. And these inductance characteristics are determined by the geometric parameters of rotor: the number of layers. the width of iron to the width of flux barrier($K_w$). slot number and shape, airgap, bridge, etc. The relationship between geometric parameters. especially, $K_w$ and motor performance will be studied. This paper shows that torque and power factor are improved through redesign with considering geometric parameters. Performance comparisons of proto type SynRM and improved SynRM are given by FEA(Finite Element Analysis).

• 한국입자에어로졸학회지
• /
• 제10권4호
• /
• pp.155-162
• /
• 2014

The internal temperature will change depending on operation conditions and material of cyclone dust collector. This study compares the results of collection efficiency and temperature distribution on the different heat flux at wall of dust collector. The previous researcher's experiment results were used to confirm the reliability of CFD(Computational Fluid Dynamics) model. Based on this verified CFD model, we extended the analysis on the cyclone dust collectors. In CFD study, we used RNG k-epsilon model for analysis of turbulence flow, fluid is air, the velocity at inlet is 10 m/s, the temperature of air is $600^{\circ}C$. Because of the difference of outer vortex and inner vortex temperature, the collection efficiency will reduce with the increase of heat flux, showed the highest collection efficiency at heat insulation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 A
• /
• pp.165-167
• /
• 1995

In this paper, the principle of the magnetic flux generation which influences the magnitude of the arc rotation in the interrupter of rotary arc type gas circuit breaker(GCB) is explained. The several factors making the phase difference between arc current and generated flux are analyzed and used to design and manufacture the rotary arc type model GCB. The magnetic flux density is calculated for the model GCB and the calculated result compared with that of the measured one.

• Korean Membrane Journal
• /
• 제3권1호
• /
• pp.24-31
• /
• 2001

Ultrafiltration membranes base on copoly(amide-imide) derivatives were prepared by the phase inversion method and the factors determining the permeation characteristics of membrane were investigated. The permeation behavior was observed by the relative ratio of permeate flux (J$\_$t/)/pure water flux (J$\_$o/). The characteristics through membrane were measured using aqueous solution of poly(ethyleneglycol) (MW 2.0$\times$10$\^$4/) over a temperature range of 10∼90$\^{C}$. With increasing the operating temperature, the relative ratio of flux became high. All the membranes had good chemical stability. Copoly(amide-imide) membranes having various Permeation properties could be obtained. Further, it was proved that the membrane performances could be determined from the preparation conditions as well as various operating conditions.

• Advances in Energy Research
• /
• 제3권2호
• /
• pp.125-131
• /
• 2015

Prompt neutron lifetime calculations have been performed for the NIRR-1 reactor HEU and LEU cores using the 1/v insertion and the Adjoint flux weighing methods. Results of calculations obtained for the HEU and LEU cores are respectively $57.3{\pm}0.8$ and $47.5{\pm}0.7$ for the 1/v insertion and $56.9{\pm}0.3$ and $46.3{\pm}0.5$ for the Adjoint flux. There is a good agreement seen between the two methods for both cores. The prompt neutron lifetime was observed to be shorter in the LEU than for the HEU as expected. However, the Adjoint flux weighing method seemed to be the easiest method in calculating the prompt neutron lifetime for NIRR-1.

• Progress in Superconductivity
• /
• 제3권1호
• /
• pp.83-86
• /
• 2001

We have fabricated a single flux quantum 4-stage shift register with interface-controlled $Y_1$$Ba_2$$Cu_3$$O_{7-x}$(YBCO) Josephson junction. The YBCO Josephson junctions showed RSJ-like current-voltage(I-V) curves at temperatures 45~80K. We tested load and shift operation of shift register with binary data sequences “1000”, “1010”, “1011”, and “1111” at 58K. For all the binary data sequences, the shift register operated successfully. By operating the circuit with proper current pulses, we observed no errors during at least 12 hours operation for all the data sequences.s.